Geophysical hazards: volcanic eruptions

Definition and characteristics

Volcanic eruptions happen when lava and gas are discharged from a volcanic vent. The most common consequences of this are population movements as large numbers of people are often forced to flee the moving lava flow. Volcanic eruptions often cause temporary food shortages and volcanic ash landslides called Lahar.

The most dangerous type of volcanic eruption is referred to as a 'glowing avalanche'. This is when freshly erupted magma forms hot pyroclastic flow which have temperatures of up to 1,200 degrees. The pyroclastic flow is formed from rock fragments following a volcanic explosion , the flow surges down the flanks of the volcano at speeds of up to several hundred kilometres per hour, to distances often up to 10km and occasionally as far as 40 km from the original disaster site.

The International Federation response adjusts to meet the needs of each specific circumstance. As population movement is often a consequence, the provision of safe areas, shelter, water, food and health supplies are primordial. In general response prioritizes temporary shelter materials; safe water and basic sanitation; food supplies; and the short term provision of basic health services and supplies.

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